The present invention relates to an apparatus and method for a drop indicator, especially a drop indicator capable of telling whether a product has ever been impacted, either in delivery or in use, by showing changes in the indicative material of the drop indicator.
In response to the market demand for compact, highly capable, and impressive-looking electronic products, product designers have made impact-related-damage prevention one of the necessary things to be considered when planning the design. The emphasis on impact-related-damage prevention has also become one of the most important gain items in the mechanical design of the products. To highlight the emphasis, the product designs are largely verified by simulated calculations and experimental results, through which repeated modifications of the mechanical design are made or additional shockproof materials are added in order to satisfy the desired specifications. Nonetheless, whenever the product is dropped accidentally or intentionally in delivery or under warranty, causing defects in the product without external damage or proof of damage, it is always the proprietor of business that is made liable for the defects and the subsequent warranty costs, which are never attributable to the consumer or whoever who really causes the accident.
Take cell phones or PDAs, for example. Usually, it is very difficult to work out whether a product has ever been dropped or impacted during the period starting from the goods being packaged and delivered from the manufacturer to the end users to the discovery of defects in the product by end users upon opening the package. To overcome the problem, various techniques have been developed to help identify whether such products as cell phones or PDAs have been dropped or impacted. Sensors, for instance, are usually used to serve the above purpose, comprising capacitive sensors, cantilever reed sensors, coiled electromagnetic sensors, accelerator/inertial sensors, magnetic/magnetrorestrictive sensors, spring mass sensors, piezoelectric sensors, and liquid pressure sensors, etc.
In U.S. Pat. No. 5,970,794, coils are used to generate magnetic fields, which vary upon shock impact. As a result, current signals are sent out to indicate that an impact has occurred.
In U.S. Pat. No. 5,983,724, a rotatable magnetic bar or its equivalents are disposed between the magnets. The rotatable body will revolve when dropped or impacted, which will cause changes in the magnetic fields. As a result, current signals are sent out to indicate that an impact has occurred.
U.S. Pat. No. 5,575,479 describes a target whose lid will open up when shot in the air, allowing colored powders to be released to indicate that the target has been shot.
Besides, in Taiwanese patent No. I255342, a reed mechanism is installed in the corner of the cell phone. The string plate device comprises two spring plates, one of which will be disengaged when impacted or dropped, resulting in the break of circuit indicating that a shock or impact has occurred.
Finally, Shock Watch Company has made a shock indicator designated with model number MAG2000. The shock indicator is mostly attached to the outside of the package containing the delivered products or machines. The structure of the shock indicator includes a box divided into two chambers with a magnet fixed at the center of one chamber and a movable metal in the other chamber. The magnetic field is in perpendicular to the collision direction. Capitalizing on the fact that magnet attracts metal, the shock indicator allows the metal to move along the collision direction when dropped or impacted, so as to indicate whether the product has ever been dropped or impacted when in delivery.